吡虫啉拌种防治小麦蚜虫技术及安全性研究

本文对吡虫啉拌种防治小麦蚜虫的防治效果、适宜剂量、对出苗和成株生长的影响以及吡虫啉在小麦籽粒中的残留进行了研究。结果表明:吡虫啉以有效成份420g/100kg种子的剂量拌种防治小麦蚜虫在整个麦蚜发生期无需再施药防治;在剂型的选择上,以高含量的拌种剂为宜,低含量的其他剂型则存在安全隐患;70%吡虫啉拌种剂拌种防治麦蚜,在试验剂量下对小麦出苗、成株期生长没有影响,具有良好的安全性;应用该方法,在小麦籽粒中吡虫啉残留量低于国家安全标准。     

土壤铅胁迫对地被竹出笋成竹的影响研究

以6种地被竹(菲黄竹、菲白竹、铺地竹、美丽箬竹、白纹椎谷笹和狭叶倭竹)为材料,设计3个土壤铅浓度处理(0、300、1500mg·kg^-1),研究土壤铅胁迫对地被竹出笋成竹数量和新竹抗逆生理特性的影响,并采用隶属函数法对地被竹出笋成竹期的土壤铅耐受性进行综合评价。结果表明:(1)土壤铅胁迫对地被竹笋期节律的影响主要出现在出笋盛期(4~5月),发笋数的降低会导致多数竹种退笋率下降,以稳定新竹数量,只有菲白竹、白纹椎谷笹、狭叶倭竹的新竹数在高浓度土壤铅胁迫下显著低于CK,降幅分别为15.87%、23.64%和31.25%。(2)土壤铅胁迫会普遍引起地被竹新竹超氧阴离子和丙二醛含量的增加,在高浓度铅胁迫下铺地竹中二者含量最低(9.96μg·g^-1、0.016μmol·g^-1),狭叶倭竹的超氧阴离子含量最高(15.99μg·g^-1),菲黄竹的丙二醛含量最高(0.021μmol·g^-1)。(3)与其余4个竹种不同,在土壤铅胁迫下白纹椎谷笹和狭叶倭竹不能显著积累游离脯氨酸,细胞渗透调节作用弱。(4)6种地被竹在出笋成竹期对高浓度土壤铅的耐受性排序为:美丽箬竹(0.79)>铺地竹(0.75)>菲白竹(0.70)>狭叶倭竹(0.49)>白纹椎谷笹(0.39)>菲黄竹(0.38),其中美丽箬竹、铺地竹和菲白竹出笋成竹数量正常,且具有较强的抗逆生理特性,具有在高浓度土壤铅污染地区应用的潜力。     

二化螟水稻类群与茭白类群成虫羽化节律和交配节律研究

比较研究了二化螟Chilosuppressalis(Walker)水稻类群与茭白类群成虫的羽化和交配节律 ,研究结果表明 :两类群的羽化节律大体一致 ;但交配节律存在明显差异 :水稻类群成虫的交配高峰出现在熄灯后 4 5h ;茭白类群成虫的交配高峰出现在熄灯后 7 0～ 7 5h。     

两种稻田摇蚊采集方法的比较

本文介绍了一种较为简便和节省人工的稻田摇蚊田间取样方法:笼罩法,并将笼罩法得到的稻田摇蚊群落结构和发生动态和吸虫器法得到的结果进行了比较。研究结果表明:在水稻的4个生育期中,笼罩法和吸虫器法均采集到了中华摇蚊Chironomus sinicus Kiknadze,Wang,Istomina&Gunderina;台湾长跗摇蚊Tanytarsus formosanus Kieffer;云集多足摇蚊Polypedilum nubifer Skuse和刺铗长足摇蚊Tanypus puncitpennis Meigen,而吸虫器法还采集到微小沼摇蚊Limnophyes minimus Meigen。其中中华摇蚊和台湾长跗摇蚊为优势类群,笼罩法取样得到的两种优势种种群密度均高于吸虫器法的,例如在拔节期时笼罩法取样得到台湾长跗摇蚊的种群密度是吸虫器法的22倍。通过取样变异系数的比较发现,两种方法精确性都并不理想,在今后的试验中可以通过增加取样的样点量或取样面积来提高精确度。相比较而言吸虫器法操作复杂,而且较为耗时,在实际操作中往往受到一定条件的限制,而笼罩法则具有操作简便、准确度高等优点,试验安排可以进行高频率取样,能够更准确地反映田间摇蚊的种群动态。因此,笼罩法为以后研究与摇蚊生活习性相似的稻田节肢动物类群(如蚊科昆虫)提供了一种新的取样方案。     

小麦种质贮藏过程中生活力丧失特性及田间出苗率表现

通过对贮藏2～20年的378份中期库小麦种质进行生活力测定(每一贮藏年份测定种质份数为10～30),结果表明贮藏年限为2～12年的种质平均发芽率都高于83％,而贮藏年限为15年的种质平均发芽率已降至20％,这表明小麦种质在中期库贮藏过程中,生活力丧失存在着骤降特性。同时对同一品种分别来自中期库低活力和长期库高活力种质进行田间出苗率和农艺性状调查,发现中期库种质的室内发芽率与田间出苗率相关极显,其相关显性高于长期库种质,且不论是来自中期库低活力种质还是长期库高活力种质,总体上田间出苗率都比室内发芽率低20％以上,在子一代种子的农艺性状上两之间无显差异。     

埋深和播种密度对豚草种子出苗及幼苗生长的影响

豚草是一种全球性的恶性入侵杂草,给我国生物多样性及经济发展造成了巨大威胁。为研究豚草种子出苗和幼苗生长的影响因素,采用盆栽实验分析了种子大小（L、M、S）与埋深（2、4 cm和6 cm）或播种密度（2、4粒/盆和8粒/盆）对豚草（Ambrosia artemisiifolia）种子的出苗和幼苗生长的影响。研究结果表明,埋深对豚草种子出苗的影响高于播种密度及种子大小的影响,较浅的埋深有利于豚草种子出苗;出苗率在不同播种密度下均具有较高水平,达到67.9%-100%,这种高出苗率是豚草在不同生境成功定植的原因之一。豚草的幼苗生长受埋深或播种密度的影响大于种子大小的影响,且小种子更易受埋深或播种密度的影响。种子大小显著影响豚草幼苗的株高和基径（P<0.05）,总体上较大种子的株高和基径高于小种子,此外更小的种子会将生物量更多的分配给根以促进幼苗的生长。幼苗的株高和基径在较浅的埋深下更高,而豚草幼苗的单株生物量、单株地上和地下生物量随埋深的增加而增加。播种密度的增加会加剧豚草幼苗之间对水分、营养、光照等资源的竞争,导致其单株地上、地下及总生物量显著降低（P<0.05）。研究发现豚草在浅埋深、低密度生境中更容易入侵成功,因此可以通过对土壤进行深翻,采取替代控制,种植竞争能力强的本地植物等手段有效管理和防治豚草。     

生物土壤结皮对种子萌发和幼苗建植的影响研究进展

生物土壤结皮（BSC）在陆地生态系统中具有重要的生态地位,尤其是旱地生态系统中,BSC占据了种子植物之间的广阔地面。因此,BSC的发展必然影响种子植物更新过程与植被空间格局;但其作用方式、影响程度等因相关研究涉及多气候要素、土壤类型、BSC组成物种和种子植物物种的差异及其不同组合,导致目前的研究结论存在广泛争议。研究综合论述了BSC改变地表微形态对种子传播过程的影响;BSC改变土壤特性（物理、化学、生物学）对种子萌发和幼苗存活与建植等关键环节的影响;并结合种子形态特征及种子萌发、幼苗建植的性状等,综合分析了BSC对种子传播、种子萌发与幼苗建植等更新过程的潜在影响机理;探讨了目前研究矛盾性结论产生的原因。总体来说,深入研究并全面揭示BSC对种子植物更新过程的影响,应加强学科交叉,将分子生物学、植物生理学、生物化学等微观研究,与遥感、野外生态因子过程监测、控制实验等宏观、中观研究结合,从机理到过程方面动态研究BSC对种子植物更新过程的影响,并引入水文模型、气候模型、种群动态模型等模型预测方法,研究气候变化、各类干扰频发的情景下,BSC对种子传播、萌发及幼苗建植过程的潜在影响,以期促进对BSC与种子植物间相互关系的研究,加深对干旱脆弱生态系统植被发展规律的认识。     

Public reasoning about voluntary assisted dying: An analysis of submissions to the Queensland Parliament,Australia

The use of voluntary assisted dying as an end‐of‐life option has stimulated concerns and debates over the past decades. Although public attitudes towards voluntary assisted dying (including euthanasia and physician‐assisted suicide) are well researched, there has been relatively little study of the different reasons, normative reasoning and rhetorical strategies that people invoke in supporting or contesting voluntary assisted dying in everyday life. Using a mix of computational textual mining techniques, keyword study and qualitative thematic coding to analyse public submissions to a parliamentary inquiry into voluntary assisted dying in Australia, this study critically examines the different reasons, normative reasoning and rhetorical strategies that people invoke in supporting or contesting voluntary assisted dying in everyday life. The analysis identified complex and potentially contradictory ethical principles being invoked on both sides of the debate. These findings deepen our understanding of the moral basis of public reasoning about end‐of‐life matters and will help to inform future discussions on policy and law reform. The findings underscore the importance of sound normative reasoning and the use of caution when interpreting opinion polls to inform policy.     

Posteclosion behavior of the flesh fly,Sarcophaga crassipalpis: A comparison of wild-type and unicorn mutants

Newly emerged flies go through a stereotypic behavioral pattern of walking, grooming, abdomen contraction (pulsing), and active uptake of air (pumping). These behavioral activities can be readily distinguished on the basis of hemolymph pressure changes. Wild-type flies and a unicorn mutant that fails to properly retract its ptilinum show identical patterns of posteclosion activity. However, a portion of the unicorns do not fully expand their wings and abdomen. Such flies are missing only the pumping component of the normal behavioral repertory, thus implying that pulsing and pumping are independently controlled.     

Addiction,Voluntary Choice,and Informed Consent: A Reply to Uusitalo and Broers

In an earlier article in this journal I argued that the question of whether heroin addicts can give voluntary consent to take part in research which involves giving them a choice of free heroin does not – in contrast with a common assumption in the bioethics literature – depend exclusively on whether or not they possess the capacity to resist their desire for heroin. In some cases, circumstances and beliefs might undermine the voluntariness of the choices a person makes even if they do possess a capacity for self‐control. Based on what I took to be a plausible definition of voluntariness, I argued that the circumstances and beliefs typical of many vulnerable heroin addicts are such that we have good reasons to suspect they cannot give voluntary consent to take part in such research, even assuming their desire for heroin is not irresistible. In a recent article in this journal, Uusitalo and Broers object to this on the grounds that I misdescribe heroin addicts' options set, that the definition of voluntariness on which I rely is unrealistic and too demanding, and, more generally, that my view of heroin addiction is flawed. I think their arguments derive from a misunderstanding of the view I expressed in my article. In what follows I hope therefore to clarify my position.